{Mjagkova Jana. 12.09. vivod vozm}

program Project4;

{$APPTYPE CONSOLE}

uses
  SysUtils;

var
 C,i,k,f,n:integer;

begin
 Readln(n,k);
 f:=n-k;
 For i:=2 to n do
   n:=n*i;
 For i:=2 to k do
   k:=k*i;
 For i:=2 to f do
   f:=f*i;
 C:=n div (k * f);
 Writeln(C);
 Readln;
end.
